scholarly journals Mechanical and thermal-expansion characteristics of Ca10(PO4)6(OH)2-Ca3(PO4)2 composites

2006 ◽  
Vol 38 (3) ◽  
pp. 245-253 ◽  
Author(s):  
G. Ruseska ◽  
E. Fidancevska ◽  
J. Bossert
Keyword(s):  
Thermal Expansion ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Thermal Equilibrium ◽  
Volume Fraction ◽  
Applied Model ◽  
Proposed Model ◽  
The Subject ◽  
Model Equations ◽  
Synergism Effect

Three types of composites consisting of Ca10(PO4)6(OH)2 and Ca3(PO4)2 with composition: 75% (wt) Ca10(PO4)6(OH)2: 25%(wt) Ca3(PO4)2; 50%(wt) Ca10(PO4)6(OH)2: 50%(wt)Ca3(PO4)2 and 25 %(wt) Ca10(PO4)6(OH)2: 75%(wt) Ca3(PO4)2 were the subject of our investigation. Sintered compacts were in thermal equilibrium, which was proved by the absence of hysteresis effect of the dependence ?L/L=f(T) during heating /cooling in the temperature interval 20-1000-200C. Sintered compacts with the previously mentioned composition possess 26-50% higher values of the E-modulus, G-modulus and K-modulus indicating the presence of a synergism effect. Several proposed model equations for predicting the thermal expansion coefficient in dependence of the thermal and elastic properties of the constitutive phases and their volume fractions, given by: Turner, Kerner, Tummala and Friedberg, Thomas and Taya, were used for making correlations between mechanical and thermal-expansion characteristics of the Ca10(PO4)6(OH)2 - Ca3(PO4)2 composites. Application of the previously mentioned model equations to all kinds of composites leads to the conclusion that the experimentally obtained results for the thermal expansion coefficient are in an excellent agreement with the theoretical calculated values on account of the volume fraction of each constitutive phase and with all applied model equations, with a coefficient of correlation from 98.16-99.86 %.

scholarly journals A New Equation for the Determination of the Thermal Expansion Coefficient of Particulate Composites

1996 ◽  
Vol 5 (1) ◽  
pp. 096369359600500
Author(s):  
A. R. Boccaccini
Keyword(s):  
Thermal Expansion ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Volume Fraction ◽  
Particulate Composites ◽  
Volume Fractions ◽  
Original Analysis ◽  
Experimental Values ◽  
New Equation

A new equation has been derived for the determination of the thermal expansion coefficient of isotropic particulate composites. An original analysis by Tummala and Friedberg was modified by incorporating the dependence of the internal thermal stress on the inclusion volume fraction, as known from the literature. For low volume fractions of inclusions the new equation gives similar values to the original Tummala and Friedberg equation. For intermediate volume fractions, however (≈0.3 ≤ f ≤ ≈0.7), the present equation is shown to be in better agreement with experimental values for different composite systems investigated.

Computational Design and Development of Alumina-Nickel Droplet Composites

2016 ◽  
Author(s):  
S. Sohail Akhtar ◽  
A. F. M. Arif ◽  
M. U. Siddiqui ◽  
Kabeer Raza ◽  
L. Taiwo Kareem ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Particle Size ◽  
Thermal Expansion ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Volume Fraction ◽  
Matrix Material ◽  
Microstructural Analysis ◽  
Computational Design ◽  
Minimum Size

Computational design for property management of composite materials offers a cost sensitive alternate approach in order to understand the mechanisms involved in the thermal and structural behavior of material under various combinations of inclusions and matrix material. The present study is concerned with analyzing the elasto-plastic and thermal behavior of Al2O3-Ni droplet composites using a mean field homogenization and effective medium approximation (EMA) using an in-house code. Our material design approach relies on a method for predicting potential optimum thermal and structural properties for Al2O3-Ni composites by considering the effect of inclusion orientation, volume, size, thermal interface resistance, percolation and porosity. The primary goal for designing such alumina-based composites is to have enhanced thermal conductivity for effective heat dissipation and spreading capabilities. At the same time, other functional properties like thermal expansion coefficient, elastic modulus, and electrical resistivity have to be maintained or enhanced. The optimum volume fraction was found to occur between 15 and 20 vol. %Ni while the average nickel particle size of 5 μm was found a minimum size that will enhance the thermal conductivity. The Young’s modulus was found decreasing as the volume fraction of nickel increases, which would result in enhanced fracture toughness. Electrical conductivity was found to be greatly affected by the percolation phenomenon in the designed range of volume fraction minimum particle size. As a validation, Al2O3 composites with 10% and 15% volume fraction Ni and droplet size of 18 μm are developed using spark Plasma Sintering process. Thermal conductivity and thermal expansion coefficient of the samples are measured to complement the computational design. Microstructural analysis of the sintered samples was also studied using optical microscope to study the morphology of the developed samples. It was found that the present computational design tool was accurate enough in predicting the desired properties of Al2O3-Ni composites.

Microstructure Modeling for Prediction of Thermal Expansion Coefficient of Plain Weave C/SiC Considering Manufacturing Porosities

2011 ◽  
Vol 399-401 ◽  
pp. 315-319 ◽  
Author(s):  
Sheng Li Lv ◽  
Qing Na Zeng ◽  
Lei Jiang Yao ◽  
Xiao Yan Tong
Keyword(s):  
Thermal Expansion ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Volume Fraction ◽  
Coefficient Of Thermal Expansion ◽  
Fibre Bundles ◽  
Plain Weave ◽  
Microstructure Modeling ◽  
Crack Volume ◽  
The Matrix

The aim of this paper is to propose a microstructure modeling for prediction of thermal conductivity of plain weave C/SiC fibre bundles considering manufacturing flaws. Utilizing photomicrographs taken by scanning electron microscope (SEM), we established an accurate sub representative volume element (sub-RVE) model for carbon fiber bundles and RVE for the plain weave C/SiC composite with consideration of four classes of manufacturing porosity. The thermal expansion coefficient of carbon fibre bundles on axial and transverse coefficient of thermal expansion is calculated, respectively. Based on which thermal expansion coefficient of plain weave C/SiC is obtained with the value of 2.71×10-6 in-plain, which has a good correlation with experimental value. The influences of different manufacturing flaws on material’s thermal expansion coefficient are studied. The study shows that as the matrix porosity or crack volume fraction is increasing, thermal expansion coefficient of plain weave C/SiC is decreasing correspondingly while the speed gradually slows.

Thermoelastic Properties of a Novel Fuzzy Fiber-Reinforced Composite

2013 ◽  
Vol 80 (6) ◽  
Author(s):  
S. I. Kundalwal ◽  
M. C. Ray
Keyword(s):  
Thermal Expansion ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Volume Fraction ◽  
Effect Of Temperature ◽  
Fiber Reinforced ◽  
Thermoelastic Properties ◽  
Fiber Reinforced Composite ◽  
Reinforced Composite ◽  
Generalized Method Of Cells

The effective thermoelastic properties of a fuzzy fiber-reinforced composite (FFRC) have been estimated by employing the generalized method of cells approach and the Mori–Tanaka method. The novel constructional feature of this fuzzy fiber-reinforced composite is that the uniformly aligned carbon nanotubes (CNTs) are radially grown on the circumferential surface of the horizontal carbon fibers. Effective thermoelastic properties of the fuzzy fiber-reinforced composite estimated by the generalized method of cells approach have been compared with those predicted by the Mori–Tanaka method. The present work concludes that the axial thermal expansion coefficient of the fuzzy fiber-reinforced composite slightly increases for the lower values of the carbon fiber volume fraction, whereas the transverse thermal expansion coefficient of the fuzzy fiber-reinforced composite significantly decreases over those of the composite without CNTs. Also, the results demonstrate that the effect of temperature variation on the effective thermal expansion coefficients of the fuzzy fiber-reinforced composite is negligible.

Control of Volume Fraction of Non-180° Domains by Thermal Strain in Epitaxial Rhombohedral Pb(Zr, Ti)O3 Thick Films

2013 ◽  
Vol 1507 ◽  
Author(s):  
Yoshitaka Ehara ◽  
Satoru Utsugi ◽  
Takahiro Oikawa ◽  
Tomoaki Yamada ◽  
Hiroshi Funakubo
Keyword(s):  
Thermal Expansion ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Growth Temperature ◽  
Volume Fraction ◽  
Thick Films ◽  
Thermal Strain ◽  
Cooling Process ◽  
Volume Fractions ◽  
Oriented Films

ABSTRACTEpitaxial rhombohedral Pb(Zr0.65Ti0.35)O3films with (100) and (110)/(10-1) and (111)/(11-1) orientations were grown on various kinds of singlecrystal substrates having different thermal expansion coefficient. Volume fractions of (110) and (111) orientations in respective (110)/(10-1) and (111)/(11-1)-oriented films were almost linearly increased with increasing thermal strain, εthermal, applied to the films that wasgenerated under the cooling process after the deposition from the growth temperature to the Curie temperature.Observed saturationpolarization (Psat)was changed linearly with the volume fractions of (110) and (111) orientations, in the same manner asthe volume fractions of (001) and (101) orientations in (001)/(100) and (101)/(110) oriented tetragonal Pb(Zr,Ti)O3 filmsreported previously. These results showed that the volume fraction of the non-180o domains Pb(Zr,Ti)O3films of both tetragonal and rhombohedral symmetriescan be manipulated by εthermal, which brings possibly to control the Psat value.

scholarly journals Out-of-Plane Thermal Expansion Coefficient and Biaxial Young’s Modulus of Sputtered ITO Thin Films

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 153
Author(s):  
Chuen-Lin Tien ◽  
Tsai-Wei Lin
Keyword(s):  
Thin Films ◽  
Thermal Expansion ◽  
Thermal Stress ◽  
Young’S Modulus ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Young's Modulus ◽  
Heating Temperature ◽  
Glass Substrates ◽  
Ito Thin Films

This paper proposes a measuring apparatus and method for simultaneous determination of the thermal expansion coefficient and biaxial Young’s modulus of indium tin oxide (ITO) thin films. ITO thin films simultaneously coated on N-BK7 and S-TIM35 glass substrates were prepared by direct current (DC) magnetron sputtering deposition. The thermo-mechanical parameters of ITO thin films were investigated experimentally. Thermal stress in sputtered ITO films was evaluated by an improved Twyman–Green interferometer associated with wavelet transform at different temperatures. When the heating temperature increased from 30 °C to 100 °C, the tensile thermal stress of ITO thin films increased. The increase in substrate temperature led to the decrease of total residual stress deposited on two glass substrates. A linear relationship between the thermal stress and substrate heating temperature was found. The thermal expansion coefficient and biaxial Young’s modulus of the films were measured by the double substrate method. The results show that the out of plane thermal expansion coefficient and biaxial Young’s modulus of the ITO film were 5.81 × 10−6 °C−1 and 475 GPa.

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